A fine pigment is likely to have a strong cohesive force between pigment particles in a medium such as an organic solvent or a melted resin. Therefore, color unevenness and a remarkable decrease in coloring power are brought about in drawdowns in some cases. A further problem that occurs is a decrease in gloss of colored surfaces and coated surfaces of drawdowns.
As a method of improving the pigment dispersibility, polymer dispersants having sites having affinity for pigments and polymer sites to impart the dispersibility in media have conventionally been used. For example, a polymer pigment dispersant for a toner is known in which an azo or a disazo chromophore containing a substitution product of acetoacetanilides is bonded to a polymer (see Patent Literature 1). An example is disclosed which uses a comb polymer dispersant, known as SOLSPERSE (registered trademark), having an acid or basic site (see Patent Literature 2). On the other hand, an example is disclosed which uses a polymer dispersant as a dispersant for a pigment for inkjet recording in which polymer dispersant a chromophore having a lower molecular weight than 95% of the molecular weight of an azo pigment is bonded to a water-soluble polymer main chain (see Patent Literature 3).